Process for producing olefin polymers, olefin-polymerizing catalyst and polypropylene for biaxially oriented film produced with said catalyst

Abstract

A catalyst system for polymerizing olefins is obtainable from (A) a solid component containing (A) magnesium, titanium and halogen and an electron donative compound which is an ether or ester; (B) an organoaluminum compound, and (C) at least two electron donative compounds, including an ( alpha ) and ( beta ) compound, wherein the total amount (C) compounds is 0.01 to 1 mole per mole of (B).

What is claimed is: 
     
       1. A catalyst system for polymerizing olefins formed from the constituents comprising: (A) a solid catalyst component containing magnesium, titanium, halogen and electron donative compound as essential components, wherein the electron donative compound contained in the solid catalyst component (A) is selected from the group consisting of esters of organic and inorganic acids and ethers, wherein the esters of organic acids are esters of mono-carboxylic acids or poly-carboxylic acids;   wherein the ether is at least a dialkyl ether compound represented by the following general formula: ##STR2## wherein R 4 , R 5 , R 6  and R 7  each represents a linear or branched alkyl group having 1-20 carbon atoms, an alicyclic group, an aryl group, an alkylaryl group or an arylalkyl group provided that R 4  to R 7  can be identical with or different from one another, and that each of R 4  and R 5  can be a hydrogen atom; and   wherein the ester of an inorganic acid is at least one silicon compound represented by the following general formula:   R.sup.2.sub.n Si(OR.sup.3).sub.4-n     wherein R 2  represents a hydrocarbon group having 1-20 carbon atoms or a hydrogen atom, R 3  represents a hydrocarbon group having 1-20 carbon atoms and n represents a number satisfying 0≦n≦4,     (B) an organoaluminum compound, and   (C) at least two electron donative compounds including electron donative compound (α) and electron donative compound (β), wherein the electron donative compound (α) is an organic silicon compound represented by the following formula:   R.sup.13 R.sup.14 Si(OR.sup.15).sub.2,       wherein R 13  represents a hydrocarbon group in which the carbon atom adjacent to Si is a secondary or tertiary carbon atom wherein R 13  is selected from the group consisting of cyclopentyl, cyclohexyl, cyclopentenyl phenyl and tolyl and each of R 14  and R 15  independently represents a C 1  -C 20  hydrocarbon group, and   wherein the electron donative compound (β) is an organic silicon compound represented by the following formula:   R.sup.16 R.sup.17 Si(OR.sup.18).sub.2,       wherein R 16  represents a straight chain alkyl group selected from the group consisting of propyl, butyl and hexyl, R 17  represents a hydrocarbon group having one carbon atom and R 18  represents a C 1  -C 5  hydrocarbon group; and     wherein the total amount of electron donative compounds (C) is present in an amount of from 0.01 to 1 mole per mole of compound (B).   
     
     
       2. The catalyst system according to claim 1, wherein the solid catalyst component is produced by the method of reducing an alkoxytitanium compound in the presence of an organic silicon compound having a Si--O bond to obtain a solid product followed by treating said solid product with an ester compound, an ether compound and titanium tetrachloride. 
     
     
       3. The catalyst system according to claim 1, wherein R 15  in the electron donative compound (α) represents C 1  -C 5  hydrocarbon group. 
     
     
       4. The catalyst system of claim 1 wherein R 13  represents cyclohexyl. 
     
     
       5. The catalyst system of claim 1 wherein R 14  represents straight chain alkyl groups, cycloalkyl groups, cycloalkenyl groups or aryl groups. 
     
     
       6. The catalyst system of claim 1 wherein R 14  represents methyl, ethyl, propyl, butyl, or pentyl. 
     
     
       7. The catalyst system of claim 1 wherein the electron donative compound (β) is n-propylmethyldimethoxysilane, n-butylmethyldimethoxysilane or n-hexylmethyldimethoxy silane. 
     
     
       8. The catalyst system of claim 1 wherein the catalyst system is a propylene-polymerization catalyst. 
     
     
       9. A catalyst system for polymerizing olefins formed from the constituents comprising: (A) a solid catalyst component containing magnesium titanium, halogen and electron donative compound as essential components, wherein the electron donative compound contained in the solid catalyst component (A) is selected from the group consisting of esters of organic and inorganic acids and ethers, wherein the esters of organic acids are esters of mono-carboxylic acids or poly-carboxylic acids;   wherein the ether is at least a dialkyl ether compound represented by the following general formula: ##STR3## wherein R 4 , R 5 , R 6  and R 7  each represents a linear or branched alkyl group having 1-20 carbon atoms, an alicyclic group, an aryl group, an alkylaryl group or an arylalkyl group provided that R 4  to R 7  can be identical with or different from one another, and that each of R 4  and R 5  can be a hydrogen atom; and   wherein the ester of an inorganic acid is at least one silicon compound represented by the following general formula:   R.sup.2.sub.n Si(OR.sup.3).sub.4-n     wherein R 2  represents a hydrocarbon group having 1-20 carbon atoms or a hydrogen atom, R 3  represents a hydrocarbon group having 1-20 carbon atoms and n represents a number satisfying 0≦n≦4,     (B) an organoaluminum compound, and   (C) at least two electron donative compounds including electron donative compound (α) and electron donative compound (β), wherein the electron donative compound (α) is an organic silicon compound represented by the following formula:   R.sup.13 R.sup.14 Si(OR.sup.15).sub.2,       wherein R 13  represents a hydrocarbon group in which the carbon atom adjacent to Si is a secondary or tertiary carbon atom wherein R 13  is selected from the group consisting of cyclopentyl, cyclohexyl, cyclopentenyl, phenyl and tolyl and each of R 14  and R 15  independently represents a C 1  -C 20  hydrocarbon group, and   wherein the electron donative compound (β) is an organic silicon compound represented by the following formula:   R.sup.16 R.sup.17 Si(OR.sup.18).sub.2,       wherein R 16  represents a straight chain alkyl group selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl or hexyl, R 17  represents a hydrocarbon group having one carbon atom and R 18  represents a C 1  -C 5  hydrocarbon group; and     wherein the total amount of electron donative compounds (C) is present in an amount of from 0.01 to 1 mole per mole of compound (B).   
     
     
       10. The catalyst system of claim 9 wherein R 13  represents cyclohexyl and R 14  represents methyl, ethyl, propyl, butyl, or pentyl.